Auto merge of rust-lang#1291 - rust-lang:dependabot/cargo/serde-1.0.8…

…7, r=Xanewok

Bump serde from 1.0.85 to 1.0.87

Bumps [serde](https://github.com/serde-rs/serde) from 1.0.85 to 1.0.87.
<details>
<summary>Release notes</summary>

*Sourced from [serde's releases](https://github.com/serde-rs/serde/releases).*

> ## v1.0.87
> - Fix inclusion of tag in struct containing flattened fields ([rust-lang#1468](https://github-redirect.dependabot.com/serde-rs/serde/issues/1468), thanks [**jwillbold**](https://github.com/jwillbold))
>
> ## v1.0.86
> - Implement Serialize and Deserialize for core::ops::Bound\<T\> ([rust-lang#1466](https://github-redirect.dependabot.com/serde-rs/serde/issues/1466), thanks [**0nkery**](https://github.com/0nkery))
</details>
<details>
<summary>Commits</summary>

- [`134f268`](serde-rs/serde@134f268) Release 1.0.87
- [`c473633`](serde-rs/serde@c473633) Format with rustfmt 2018-12-10
- [`6a3a820`](serde-rs/serde@6a3a820) Merge pull request [rust-lang#1474](https://github-redirect.dependabot.com/serde-rs/serde/issues/1474) from jwillbold/master
- [`1d6ef76`](serde-rs/serde@1d6ef76) Fixed [rust-lang#1468](https://github-redirect.dependabot.com/serde-rs/serde/issues/1468), flattened struct fields made structs ignore their tag
- [`c8e3959`](serde-rs/serde@c8e3959) Release 1.0.86
- [`796f412`](serde-rs/serde@796f412) Document that Bound<T> impls exist
- [`fa854a2`](serde-rs/serde@fa854a2) Format with rustfmt 2018-12-10
- [`3a097ff`](serde-rs/serde@3a097ff) Deserialize Bound::Unbounded as unit variant
- [`8463bfc`](serde-rs/serde@8463bfc) Remove as yet unrequested range impls
- [`7a72b4c`](serde-rs/serde@7a72b4c) Merge pull request [rust-lang#1466](https://github-redirect.dependabot.com/serde-rs/serde/issues/1466) from 0nkery/master
- Additional commits viewable in [compare view](serde-rs/serde@v1.0.85...v1.0.87)
</details>
<br />

[![Dependabot compatibility score](https://api.dependabot.com/badges/compatibility_score?dependency-name=serde&package-manager=cargo&previous-version=1.0.85&new-version=1.0.87)](https://dependabot.com/compatibility-score.html?dependency-name=serde&package-manager=cargo&previous-version=1.0.85&new-version=1.0.87)

Dependabot will resolve any conflicts with this PR as long as you don't alter it yourself. You can also trigger a rebase manually by commenting `@dependabot rebase`.

[//]: # (dependabot-automerge-start)
[//]: # (dependabot-automerge-end)

---

<details>
<summary>Dependabot commands and options</summary>
<br />

You can trigger Dependabot actions by commenting on this PR:
- `@dependabot rebase` will rebase this PR
- `@dependabot recreate` will recreate this PR, overwriting any edits that have been made to it
- `@dependabot merge` will merge this PR after your CI passes on it
- `@dependabot cancel merge` will cancel a previously requested merge
- `@dependabot reopen` will reopen this PR if it is closed
- `@dependabot ignore this [patch|minor|major] version` will close this PR and stop Dependabot creating any more for this minor/major version (unless you reopen the PR or upgrade to it yourself)
- `@dependabot ignore this dependency` will close this PR and stop Dependabot creating any more for this dependency (unless you reopen the PR or upgrade to it yourself)
- `@dependabot badge me` will comment on this PR with code to add a "Dependabot enabled" badge to your readme

Additionally, you can set the following in the `.dependabot/config.yml` file in this repo:
- Update frequency (including time of day and day of week)
- Automerge options (never/patch/minor, and dev/runtime dependencies)
- Pull request limits (per update run and/or open at any time)
- Out-of-range updates (receive only lockfile updates, if desired)
- Security updates (receive only security updates, if desired)

Finally, you can contact us by mentioning @dependabot.

</details>